In 1647 the army made it clear that it was not happy about arrears in pay, no indemnity for wartime acts and drafting. Soldiers who knew about Lilburne and his group started selecting delegates (known as "Agitators") to go to Parliament with their problems. Sir Thomas Fairfax then called a rally for the whole army to discuss action. And so, the General Council of Army was formed - both the soldier class and the officer class are represented. The General Council forms its own policy, based on Lilburne's ideas.

The army split into two groups. The Grandees whome were composed of the officer class, and Lilburne's supporters whome were nicknamed the Levellers by Oliver Cromwell (second-in-command). The Levellers propose an agreement with the Officers, which was rejected because it called for religious tolerance.

After Charles I was executed, the Levellers increased their activity, John Lilburne, William Walwyn, Richard Overton and Thomas Prince were then arrested for treason and the Levellers began a mutiny in London. Cromwell and Fairfax appealled for them to stop, and they did. The head of the mutiny (Robert Lockyer), was executed. The Levellers were not pleased and put together a resistance, which was crushed by Cromwell at Burford in a surprise attack. And so the Levellers lost their military support, Cromwell leading the army to war against Ireland.

Lilburne, Walwyn, Overton and Prince were later released, but the Leveller movement was never again.

Politics

If afflictions make men wise, and wisdom direct to happinesse, then certainly this Nation is not far from such a degree thereof

The Levellers had very radical ideas about how the country should be run. Their ideas included the right to vote for all, the distribution of the landlord's land to all, equal rights, the cessation of wars with foreign lands and the empowering of the peasant class. They mustered support in the military - many soldiers being unhappy with the way they were treated and the poor people of England, but very unpopular with those in power (naturally). The Levellers eventually ran out of political steam.

Britain was primarily a monarchy, with very distinct class divisions, the thought that these divisions should be blurred was an alien concept. Even with the Civil War, and the fight against King Charles I, the Leveller's ideas were simply too radical. The country was in the throes of massive culture shock, and was being shocked constantly by Olver Cromwell. The idea of equality, whilst attractive, was not realistic.

Sources
www.libertarian.org
Agreement Of The Free People of England. By Lieutenant Colonel John Lilburne, Master William Walwyn, Master Thomas Prince, and Master Richard Overton, Prisoners in the Tower of London, May the 1. 1649.